I can definitely remove the grill and take a picture tomorrow!Given your knowledge, skill level and level of commitment, I'm thinking the previously mentioned Peavey Black Widows would be your best bet. Or the Scorpions. Physically, I think they would be a drop-in replacement, but I'm not all that knowledgeable about it, so you'd want to verify that. Replace both drivers -- if you don't, you'll probably be replacing the other one soon enough.
A pic of the cab in question might elicit some other info about fitting the different drivers -- I doubt it's as intense as has been indicated, but I guess that is a possibility. Do you know how to remove the grill?
Yeah, I'm not really that knowledgable about speakers, electronics, etc but I've just used this cab for years and love how it sounded and how loud it was. I'm not really picky or particular. I'm going on tour in a couple weeks and wanted to be able to have it working again!