@flaxxer, since you want something smaller in chassis size and want to tube roll, would suggest you try out the Chinese clone of the Marantz 7 tube preamp. Its a line stage only, has excellent sonics and you can tube roll and capacitor roll to your hearts content.
Remote PRT-07B stereo 12AX7 Tube preamplifier base on Marantz M7 preamp L12-46 | eBay
Remote PRT-07B stereo 12AX7 Tube preamplifier base on Marantz M7 preamp L12-46 | eBay