i'm not sure i get what it is you're really trying to accomplish:
- if you're using an XLR connection to get to your recording gear = you don't need an amp/speaker in the first place.
- unless you're using two inputs (e.g., 1. mic the amp, 2. go direct with XLR) = you don't need an amp/speaker.
- getting a "60's-70's warm, punchy p-bass tone" on a recording = you don't need an amp/speaker.
since a DI and/or interface (direct to your recording gear) will do: why do you need a "studio amp" to get a "60's-70's warm, punchy p-bass tone?"
how do you record your bass now? (i voted "other.")