Atari 8-bit motherboard to fit the Atari 1200XL case, it includes the main ideas of the cancelled 1450XL - designed to include a speech synthesis chip, PBI interface, and because it is a modern recreation it has optional space on the motherboard for installing modules for MIDI, UGV-II video, Sophia 2 mini-ldmi.

I'm sure you know about it from the AtariAge thread or bits of the past website.

Here is what the inventor, Dropcheck had to say about it:

(Dropcheck speaking)

• • After completing the 1450XL Replica board I realized that the 1450XL pcb was very close to the 1200XL in size. So much so that I decided to see what I could use from the 1450XL replica board in that format. As almost no one has a land line anymore and 300 baud speed is like watching paint dry, I chose to remove the modem feature. Also since there are no parallel drives or driver board to support that feature from the 1450XL I chose to also remove those parts. I also removed the RF modulator. That got the part count down enough to fit in the 1200XL pcb with some room to space. I added some additional features such as a Midi player and 800XL compatible PBI port, and hooks for the addin boards PokeyMax 2B/4, UGV II and Sophia. The PBI cutout should be the only mod you will need to do to the 1200XL case.
• The 1250XL will fit a normal 1200XL case with the need to cut an opening for the PBI connector.
• The 1250XL retains all the features of the 1450XL except for the builtin modem, PBI parallel drive connector and RF Modulator.
• The 1250XL has builtin hookups for the following addin boards, PokeyMax 2B/4, U178 Midi Player, Sophia and UGV II.
• The 1250XL has the ability to quickly be converted to PAL using the PALBurst board from @mytek, PAL OSC and PAL version ANTIC and GTIA chips. No soldering needed