Castlemaine Rod Shop (CRS) and Dellow in Australia sell bellhousings.
http://www.rodshop.com.au/
http://www.dellowauto.com.au/main.html
Rush Imports in Australia developed a kit for the 1UZ and R154 using an adaptor plate, but it needs the bellhousing from a 1JZ-GTE engine / R154 gearbox (JDM Soarer / Supra JZA70 / Chaser / Mark II).
http://www.rushimports.com.au/
Thor Racing in the UK have a kit which mates the 1UZ-FE auto bellhousing to the R154 gearbox from a Supra Mk3 3-litre turbo.
http://www.thor-racing.co.uk/Manual_Gearbo...version-311.asp
I'm surprised there's nothing available in the US, though.
EDIT:
May be useful:
http://www.v8supra.com/
http://store.driftmotion.com/productdetail...duct_id_int=233
http://www.clubna-t.com/forums/showthread.php?t=744