I popped my high E but I only have a pack of 5 strings (missing the D)... is it a bad idea to just re-string only 5 of em and leave the old D on? Yeah I could just buy another pack but I don't have a lot of disposable income.
Not a big problem. As it gets older it's going to get harder to keep in tune and maybe the intonation will get a little out of whack for it but if you're worried about something major the answer is don't worry about it.
Intonation uh? I just dished out $40 getting that problem fixed... will it really get messed up from just a few weeks of differently aged strings?
Why not just restring the E...keep the rest for little changes if this happens again.
Yeah nothing major but it's always good to have a proper guitar stringed and all...

It depends on how much you care about playing a 6-string guitar.
"We weren’t too ambitious when we started out. We just wanted to be the biggest thing that ever walked the planet."
-- Steven Tyler
Intonation doesnt usually change much once its set. It will change if you mess with the action or change guage of strings.
It'll be fine.

...I used to be in WNx...
Recognized by the Official EG/GG&A Who To Listen To List 2008
Quote by utsapp89
^I'd let a pro look at it. Once you get into the technicalities of screws...well, it's just a place you don't want to be, friend.