>>6
Here you can download free.

ITRON
TOPPERS Project http://www.toppers.jp/en/index.html
TOPPERS JSPkernel http://www.toppers.jp/en/jsp-kernel-e.html

T-Kernel
T-Engine Forum http://www.t-engine.org/index.html
T-Engine Forum http://www.t-engine.org/T-Kernel/tkernel.html

CTRON
CTRON Home Page (in English) http://www.sakamura-lab.org/TRON/CTRON/home.html

And here, you can buy BTRON.
Personal Media HOME Page Greeting (ENGLISH) http://www.personal-media.co.jp/welcome-e.html
English Language Kit http://www.chokanji.com/download/ck4eng.html

>>8

> Does TRON have a Gui?

Yes, BTRON has a GUI.
Please read these.

Resourceful TRON
http://chokanji.hp.infoseek.co.jp/
TRON Web
http://tronweb.super-nova.co.jp/homepage.html

> Where can I see screenshots of it?

Link
http://tronweb.super-nova.co.jp/btronproducts.html
Shots
http://www.eva.hi-ho.ne.jp/mitsuda/
http://www-wa0.personal-media.co.jp/ck/pictures/ck4scr.gif
http://www.eonet.ne.jp/~nisaka/_tP-jF-K.html
TeaCube
http://images.google.com/images?hl=ja&q=T-cube&lr=&sa=N&tab=wi

> Is it dual-bootable with Windows XP?

Yes.
You can do BTRON dual-bootable with Windows XP/2000/98SE/98/95.