what's your vertical and horizontal measurements for the door and which way do you plan to run the grain?

Normally the grain runs vertically.

Two issues I can think of:
1. Warping and twisting. Chances improve with good selection of wood, preferably straight-grain and quartersawn.
2. Cross-grain expansion and contraction seasonally. Not so bad for overlay doors. Could be a killer for inset doors.

Hmm.
I was planning maple, and it's roughly 8" tall x 16.5 wide. x2 for a 36" wide cabinet.

One of my considerations was the grain, which on doors usually runs vertically. I could piece them together, biscuits or Jig, and cut them down.

I've noticed most doors are more than one board. I was guessing this was for stability?

I'm going inset, which creates its own difficulties. I'd probably piece a Shaker type door, or something with other pieces attached. I think this would prevent twisting.

Just running this through my head. I like to explore all the options. If I see it not done, but it seems ok to me, there must be a reason I'm not seeing it!

Most doors are more than one board because narrow boards are cheaper than wide boards. Depending on the care used in orienting the boards (generally none in commercial cabinets) it might make them more stable-- if you flip the orientation of every other board so that the crown varies direction you can (in theory) make a panel that will stay flatter. Some even advocate ripping a wide board and flipping every other one. I would instead choose boards with vertical grain and make sure they're well-equilibrated to your general humidity level prior to jointing and planing to thickness. It's also important to use construction methods that allow for the wood movement--floating panels, slotted screw holes, avoiding cross-grain joints, etc.

I've used cherry and maple boards up to 28 in wide in tabletops and they work just fine. 8" should be easy with just a little care in picking the boards.

16.5" boards are going to have significant movement seasonally and I would not try to inset them.

If this is your plan, I suggest using maple plywood and edging with veneer tape or solid wood. Plywood will also significantly reduce the risk of warping.