The "Harrisburg" show is actually in Carlisle and replaced the
Central Pennsylvania Reptile Expo as it's at the same venue. I won't attend that one on principle because of one of the promoters and how the show came about...If you'd like to know in detail, PM me...I'm not about to get into it on a forum.
My suggestions has always been the Mid-Atlantic Reptile Show. I haven't gotten to it the past two years, but in years previous, it was a GREAT show and I thoroughly looked forward to it every year. Maybe this year!
All of Rick's shows (Havre De Grace, Richmond, Manassas) are tiny, but if you're just after rodents, I know the guy I purchased rodents from goes to them. You might also luck into some pretty neat finds this time of year.
I know there's a Pittsburgh show, but I've never been to it...Maybe someone else could chime in about that one?
Depending on how many rodents you need, I have a guy that delivers to me that I might be able to get you into contact with. Orders would have to probably be pretty decent in size for him to even consider it though.