Any aftermarket (built or bought) bullpup stock is illegal. The only way bullpup stocks are LEGAL, is if they are built as an integral part of the gun, whereby the gun can not be fired outside of the stock.
A 10/22 CAN be fired without a stock, therefore, any bullpup stock for it is illegal.
If you're just keeping the bolt/barrel/trigger housing, and NOT the receiver, you're manufacturing a firearm (receiver) which has it's own issues.
Get over it - you can't/won't be able to own a bullpup 10/22.