No problem to rebuild at all. Why don't you try it yourself?
A good guide to replacing rims here.
http://www.sheldonbrown.com/wheelbuild.html
It looks very complex, but isn't really.
As a first attempt, why not get another front rim to match the rear one? Then tape it side by side onto the old front rim and move the spokes over.
Front wheels are generally easier to work on than rear ones I find. As for spoke lengths, explain the plan to the LBS and ask for a suitable rim. Having said that I've never had an issue with spokes not matching, maybe I've been lucky. Get a few spare spokes and nipples, just in case 😉