Gents, 
Be very careful guestimating the cost of shipping a frame from US in the mail.  Its little short of astronomical. 
A VMX friend in the US looked into it for me about 6mths ago & came to conclusion you'd get little change from US$500!! (as I recall) Just ridiculous.
I looked into it myself just using info on the web & came to a similar ballpark figure (tho a bit less). There maybe other cheaper options, but I quickly gave up on the idea. 
If anyone knows more realistic options, I'd love to hear them.
Love the project Oldie. I see no prob using mod'd TS frame. They're actually quite light. I do suggest you brace the swingarm 'arms' near the pivot as the stock swingarm is very flimsy & seems to me to account for much of their somewhat undesireable handling 'quirks'. 
Love to see more progress pics