There will be plenty of after-market alternatives, where you replace the whole housing, but the easiest solution, where you keep the actual headlight unit and front of the housing, is to swap out the stock 'bucket' with that of the XSR900:
I would love a new headlight as well. I really hate the look of the one of the 700. I considered the 900 mod but £90 quid for a bit of plastic seems a bit steep to me. I was looking at getting a LED headlight and a new bucket, quite a few on eBay that won't break the bank.
Resurrecting this thread as I'm looking for that same information, as in John876's post. How does that LED headlight unit connect?
My XSR came with that same type fitted. I haven't had the opportunity to try it out after dark yet, but it seems Ok.
Except that, with ignition on, there is no pilot light or dip beam showing. So no lights showing at the front of the bike (but tail light is on), until engine starts, then all Ok.
So if anybody has fitted this particular LED light and has the fitting instructions, I would like to see them.