Anyone ever seen a Carbine like this?

Sounds like a Universal in a Plainfield stock

All those post war carbines are researched here

http://www.m1carbinesinc.com/index.html

Tim

Universal, Iver-Johnson, Plainfield, and AMAC all made the Enforcer. Early Unversals had the GI style 1 Spring receiver that used GI parts and had a Micro-Groove Barrel then they started making the 2 spring slide/oprod that does not use GI parts or Stocks. Iver Johnson also made the GI style but has a different barrel band. I have seen variations in the trigger housing. I have 2, both original manufacture, both can use GI parts. Fun little bullet hoses!

The carbine shown could be a Plainfield Commando or Iver Johnson PM30P Paratrooper, both makers used similar stocks.
Plainfield was considered the best carbine clone on the market and was made up of USGI surplus parts except for the receiver which was made by Plainfield Machine.
Iver Johnson used some USGI parts but the receiver was made by Iver Johnson as was the trigger housing which was somewhat larger than the USGI and was of an aluminum alloy.
The carbine you show and discribe is an Iver Johnson make.
The Enforcer was manufactured by Universal, and later by Iver Johnson after Iver Johnson bought out Universal, which was strictly a pistol configuration. It did not meet an eager market and was discontinued after a fairly short run.
When USGI parts became unavailable en mass Plainfield ceased production.
The first iteration of Universal and Iver Johnson were well accepted by the market until they started changing the basic internal operating system configuration and the use of lesser quality materiels.
The Plainfield Commando, Iver Johnson PM30P, and the Universal Enforcer pistol are now becoming items of interest by collectors.