I think using jpct for drawing 2d raster map and some vector data over it (if I understand correctly your needs) is overkill. Basicly, at any moment, you have position, rotation and scale of the map, right? So, assuming you stick to the standard Java MVC pattern you need to design and implement:
1. MODEL - a way to load and represent vector data (doesn't matter if it comes from AutoCad or from some other source) over raster data
2. VIEW - a way to display data in it's current state (position, rotation, scale)
3. CONTROLLER - a way to interact with the user and let him change position, scale, rotation

A site with many java GIS projects with source for inspiration:
http://opensourcegis.org/

On the other hand jpct can display textured planes (scaled and rotated raster data) and wireframe meshes (scaled and rotated vector data)... out of ideas here, but hope I helped a little

Try thicker wall and/or smaller speed.

And is it possible that image created on the fly (e.g. ImageIcon painted by Graphics) can be used as textures to be drown in this manner, and in GLCanvas mode?

Sure, construct an Image, add it to the texture manager (or modify existing texture), apply the texture to an object and here you go.

hmm, if focus is on rendering quality and the renders are done on the server you could use renderer like povray, yafray, blender renderer.... and a lot more options here. of course, you have to properly tune rendering quality, so it looks nice and doesn't take forever (how nice - it depends on your server speed (if you have render farm you can perhaps even afford GI and the load of the web application - how many users are using it, how responsive it has to be and so on). your web application just prepares the scene and calls the external renderer.

forget about the .max format - it is supported only in 3ds max. but you can always easily convert to .obj or .3ds - they are widely supported.

jpct is suitable for realtime rendering - for example if you want to make an online 3d editor of the room DevKit seems quite suitable for a foundation.

Can't you write a small MaxScript that exports every n-th frame of animation (or search the net for a ready such script)? So you get rid of the tediousness of the export process
Never touched 3d studio, just theorizing

So then you have to find a codec that encodes video at least at real time speed on your hardware... don't know how hard this task is, you can loot at ffmpeg - it's popular free open source codec and it has java wrapper also

Congratulations for your 100000 post! (in binary

I have several UV maps for my model because my model is built in parts.  I don't see how people texture a single UV map for an entire model at once.

Your UV map doesn't need to be continuous, you may have islands. Also, your model's parts can share single texture, just make sure each part's uv coordinates doesn't overlap with the others. See character's uv layout here (Google for many more examples):
http://accad.osu.edu/~fkalal/753/hw2/hw.html
This concrete character is a single mesh, but it's not nessessary.

So I suggest you improve your unwrapping and drawing skills and keep your job with JPCT easier

Edit: Oh, and this was my 10000 post!

Ok, I see your point, but:
1. The engine, by its nature isn't really user friendly. It's nice designed and implemented and developer friendly, though
2. The community is not quite big, maybe because people are more comfortable using c/c++ for making games, because this way has much more traditions and people have done it many, many times
3. There's a Feedback subforum already. Everyone can share what he/she has done. If the information that can be clearly classified into category 'Tutorial' grows it can be moved to another specialized subforum, but this is not the case in the present moment, I think.