I think this sounds like a great idea. I notice that you are in ohio, so the full sun will not be as bad of a problem as it could be. Having said that, your trees still could get some leaf burn in late summer. Many cultivars of japanese maples do have a layering habit, but a little pruning enhances this quality. You are right about the 'bloodgood' being an upright large (for JM standards) tree. It would likely get 30 ft high and 20 or so wide in a reasonable time (and in like 50 years significantly larger). There are hundreds of cultivars, so recommending just a few would be difficult. However, we can give a few good common trees, and you can check around to see what's available. There are several semi-upright reds that are considered smaller than 'bloodgood'. Unfortunately, most growers do not shape their uprights to have a nice spreading shape. They pack them in tight and the trees grow straight up, but you might be able to find a few oddballs that have started getting some horizontal branching. 'Fireglow' is supposedly a smaller red with similar color to 'bloodgood' (there is conflicting information as to its size, it may get almost as large as 'bloodgood'). The habit will be similar, but you might find a tree with good horizontal structure. 'Moonfire' is another similar tree, probably with more purple than the above. There is also conflicting information about this tree, some say it is as large as 'bloodgood' and some say half the size. Judging from the trees I have seen, I would say it is on the smaller end of that range. It seems to have more horizontal growth and less long leggy limbs. 'Pixie' is a dwarf red similar to 'bloodgood' in color (perhaps not holding quite as long), but much smaller. Many of these trees I have seen had good layerered branch structure. However, it is difficult to tell whether this was natural or trained. There are several others and some other folks will probably reccomend a few more like 'shin deshojo', but I'll move on. There are many greens that could fit into this middle sized layered type. I don't know where to start here, but perhaps a weeping variety like 'waterfall' or 'viridis' would be good. They will usually spread wider than tall, but they are often staked and pruned to be more upright or mushroom shaped. There are several mid sized trees like 'tsuma gaki' that would be beautiful (although it might not do well in the sun), but the likelihood of finding one at a local nursery is slim. As far as low mounding types, a red weeping dissectum like 'crimson queen' could be used here if it hadn't been staked. It will grow more or less horizontally and along the ground if untrained. However, it can get quite wide in the 10 ft range. There are several dwarf shrubby types like 'shaina' that you might run accross that would be signifcantly smaller and have a low mounding habit.

@Bayarea_girl z9ca I have a JM on my front yard that's upright and stands at about 15ft plus tall. The leaves on my JM don't turn green and stay red all year round. Even if it's extremely hot abd sunny in the Summer it just turns into a darker red like more of a purple/wine coloured shade of red instead of it "Bronzing out" like @gardengal48 (PNW Z8/9) said. I'm not sure what type of JM i have but through the seasons i know my JM turns into a really super bright almost neon red in the Spring, then during the Summer it turns into a purplish/wine coloured red, in the Autumn/Fall it changes to a brighter blood red color until the Winter time when it turns into a darker burgundy colored red four like a week then all the leaves fall off.

A lot of the reds, upright or weeping, turn green or red-green mid-summer. Sometimes it's just how that cultivar behaves, sometimes it needs more sun to stay red. It's not always a bad thing, though-- often the ones that have turned green will push out new red growth, and that looks pretty. Is your tree planted in shade or part-shade? What zone are you located in?

Thank you! Thank you! I was so afraid that everybody was going to say "Absolutely NOT!" and I've REALLY been wanting a JM for a while now. I've looked at some picture of Twombly's Red Sentinel and while I like it, I'm not entirely crazy about it's non-traditional shape. I saw a Fireglow in person at a local nursery the other day and fell in love with it. I'm going to check out the other varieties you mentioned too. Really liked pictures I saw of the Okagami and Umegae. Also just noticed that the Umegae is the favorite mentioned here: http://www.davidsansjapanesemaples.com/featured-japanese-maples/favorite-japanese-maple/ I'm hoping to have the JM in the middle of the bed and then fill in the remaining areas with hostas, heucheras, hellebores, astible, ferns etc.