Bob - that does look nice! Your several repaintings payed off in the end, it looks like.
As for an extension, I'm going to have to say no, for several reasons. First off, I'm a stickler for time frames, mostly because it forces ME to motivate to get stuff done. All too easy to push something on to the back burner in favor of something else I can do that might require a bit less effort. Heh. Secondly, even waaaaay up here in the north, winter is pretty much over. Going out on my bike today, mid 50's, and the next couple of days potentially hitting 60! I really want to keep these WW builds somewhat in the right season...just feels wrong to be applying whitewash when the birds are chirping and the grass is growing. Finally, I have lots of other GB's I'm in that I want to be able to give my full attention to, as well as lots of other good ideas for GB's that I want to host. Rest assured, however, that there WILL be another WW build next winter.
NOW, that all being said, it looks to me like you're just about there! In fact, I'd say that for some people's tastes you're already done! I would have no problem awarding a badge to your build in it's current state. If you do manage to swing the other effects on there, that would be a bonus, as far as I'm concerned. BTW, I know some good coffee brands if you need that extra push...