You would not pay for one in a tree shape, with an elevated head and cut that down to a stump. That would throw away paying to have one so developed by a production nursery. You could try managing such a specimen as a sort of pollard, cutting back annually at the end of winter to a head of short stubs, at the top of the trunk.

Most I see at garden centers have been developed into a tree shape and priced accordingly. However, if you wished to grow one as a bush, that was cut down to near the ground every year a smaller, untrained specimen could probably be found fairly easily among mail-order catalogs.

Unlike many people I actually like them in bush form (as well as tree form). I have both. Last fall I bought two Forest Pansy Redbuds that were only about 2' tall and shrubby and they had the most gorgeous fall color that I've ever seen on a Forest Pansy, out of this world.

Why I'm asking about harsh pruning (as in close to ground) is I have one that was a tree but has had so much die back that it is a tree trunk with only one branch coming out of the trunk, not very attractive. I'm thinking I'd prefer it as a shrub vs. what it currently looks like and perhaps a harsh prune many envigorate it but before I do a harsh pruning on it (e.g., 1' from ground) I want to have some idea I wouldn't kill it.

For me it is all about color of leaves, particularly fall color of leaves so whether it is in tree form or shrub form I just want great fall color. I found the comment in the book about a harsh pruning on Forest Pansy yielding best color leaves intriguing and it makes me wonder if the 2' shrub Forest Pansy Redbuds I bought this fall had out of the world fall color due to a hard pruning which left them in shrub form. The 2' ones I bought are vigorous full multitrunked sort of like a Forsythia, are not newer seedlings.

Pruning reduces overall volume of growth until previous foliage and stem mass is recovered (after pruning is discontinued). Plant rushes to replace lost top growth after hard pruning, creating appearance of increased plant vigor. But the number and volume of replacement stems is less than what was present before hard pruning.

Renewal or renovation pruning changes the shape of the specimen, not its health. Redbuds are prone to pathogenic infestations that kill back the tops, likely yours is having this problem. Cutting off the top may not clear this up.

Issues with your redbuds aside, hard pruning (coppicing/pollarding) of appropriate species DOES tend to accentuate foliage, both in size and often, in coloring as well. An example would be smokebushes, Cotinus coggygria cultivars, which are frequently treated this way to enhance foliage effect. I have not encountered any evidence to indicate this would necessarily improve fall color -- that is typically determined by the species itself and growing/climate conditions, rather than by the pruning alone.

Hard pruning will eliminate or drastically reduce flowering on most plants. You are giving up flowers for the increased foliage effect. Since that is one of the primary reasons - maybe the only valid reason - for growing redbuds (especially in the PNW where they seem to have multiple health issues), I might choose to opt for the smokebush (or a purple leafed ninebark or possibly weigela) that lends itself to a much more shrubby form and has great in-season and fall color as well.

Regarding 'Redbuds are prone to pathogenic infestations that kill back the tops, likely yours is having this problem. Cutting off the top may not clear this up.' -- is there any reason NOT to try a hard prune to see if it comes back stronger? I'm not happy with how it looks right now but if I risk killing it with a hard prune I'll leave it alone. If it likely wouldn't kill it it will be worth a shot.

Regarding alternatives to Forest Pansy Redbud here in the PNW I already have these plants so I'm trying to make them look as good as they can vs. give up on them.

I've chosen not to grow a Redbud here because of it's problems, but there is a good alternative that looks a lot like a Redbud in leaf and has no problems that I'm aware of. It's a Disanthus cercidifolius. Fall color ranges from a deep purple to red and yellow depending on exposure. The blossoms are rather insignificant.
Here's one of mine.

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Good suggestion, Mike! I had forgotten about Disanthus - it is my preferred redbud alternative as well. Outstanding fall color and the "cercidifolius" species name indicates just how much like a redbud (Cercis) it is, at least in foliage attributes. And tough, hardy plant as well.

Not sure it is much help to the OP however, as he indicates he already has the redbuds on hand.

Not really in the same league, much more of a collector's shrub and like its witch hazel family relations wanting a woodland garden situation rather than the open one desired by redbuds in this comparatively dull and cool climate.