There have been several threads on the subject of building trailers, do a search here on the RCU for some great ideas.

A regular supplier of trailer kits is 'Harbour Freight' I beleive that they are out of California and they ship everywhere.

Plan 'B' is to visit a local trailer store and buy an old camper trailer that is a mess - strip it down to the frame and then build from there - often these dealers just want to get rid of "JUNK" and the prices are very good.

Good Luck!