Doylestown Glass Company will drill glass for you. At least they did a while ago. Haven't been there in years. It's also maybe far depending where "Phillyish" exactly is for you. There's another glass company in Norristown but I've never dealt with them.
I'm planning on doing a fish bridge between two aquariums because they're in a space where I can't put anything bigger. I was thinking about putting holes in the glass then running clear pipe between them, but I'm pretty sure the glass won't be able to handle near that amount of weight. I'm instead considering bending the plastic and running it up and over the tops, which is closer to my original plan. I can support it apart from the tank much easier if it's not siliconed to the tank.
We'll see, it's still in the conceptual stage at this point.
Do they have a retail shop though? Their website is kinda vague on the issue. I emailed them for a quote on cut acrylic sheet to make a custom tank and it was pretty high, but that's a great price for the tubing.