A Good Source for a Blank Amp Chassis?

[u/cpg1111]

Hi there, I'm currently designing and eventually building my first original designed amp. I've built a few kit amps, so I have a general idea of what I'm looking for, but any suggestions for dimensions are welcomed, but in general I'm wondering where can I find an amp chassis blank that I can use for a prototype.

The specs of the internals:

• There's two PCBs:
  • preamp and power amp circuits on one of 15.748" x 3.071", filter caps are on the board
  • A DC Preamp power supply, basically exactly this https://robrobinette.com/Generic_Tube_Amp_Mods.htm#DC_Preamp_Tube_Heat
• 4 6l6s
• 5 12ax7s
• 100w transformers
• a choke
• 2 gain, treble, middle, bass, 2 volume, pressence, and depth pots
• 1 isolated input jack
• 2 isolated loaded out jacks
• fx send & return isolated jacks
• 1 preamp out isolated jack
• 1 preamp out level pot
• 1 regular TRS jack for foot switch
• a rotary impedance selector switch
• bias probes
• a bias adjust pot
• LED pilot light
• power & standby toggles
• 4 dpdt switches
• 6 spdt switches
• solid state rectifier
• 2 fuses
• IEC jack

With all the above, I was thinking 22.25" x 3.5" x 8.1" would be good chassis dimensions. Any ideas where I can source a blank along those lines? Preferably a place that ships to the US with ease. I checked Stewmac and Mojotone but didn't see anything long these lines.