Yeah, you totally could. DV-HD is about twice the storage as DV-50, but will look pretty awesome to offline. It has a higher resolution yes, but the color space is the same as DV-50. An EDL for telecine will be less complicated from a DV-100 23.98 source, yes, but nothing more than an extra day of prep on the back-end won’t solve.
We have several FCP stations which are SD only, so it makes more sense foer us to work on the edit in DV-50 (but it sounds like you’ll be on single-station editing. So it’s not a problem.) SD also makes it quicker and easier to output quicktimes, DVD’s, or viewing cassettes (less processing). Also, when you have clients in to watch the edit, it’s easier to output to a television rather than having them gather around a 23″ Apple monitor.
I’d say go for it, edit in HD. It’ll look great. Murch did it for Jarhead and seemed happy. But I personally don’t see any immediate need to offline in HD unless there’s very specific technical considerations.
good luck