Glasspacks definitely can't be used as a replacement for the front muffler/resonator, definitely too hot there, I had them blow out too back in the day installing them up front like that too.
But I figure at the end of the system they will likely last MUCH longer but also like your idea too, a Vibrant Ultra Quiet would be a GREAT higher quality alternative. There just isn't much talk about straight replacement mufflers, I'd like to maybe try something else to bring down accel volume some, it's definitely a bit louder than I thought would be, but doing J side hotside pipe and even turbo inlet have helped with less backpressure to bring the volume down since... I guess any 18-19" long muffler with 2.25" inlet would fit with room to curve down a bit for proper exit height with room left for choice of tip... I literally just pieced that together just to get some proper sound with a Symposer delete at a low cost.