Hello Diki
I think I see what you are getting at; you want to be able to record a chord sequence on the fly, and then be able to press one button to get the sequence to loop while you play with both hands.
If this is correct, then for arranger use in a gigging situation, I can see the advantages, however as most arrangers are not sold to gigging musicians, I think you will probably not have much luck.
One suggestion I would make, (Assuming I have understood what you want correctly) is to post it on a lot of different forums, to see if you can get others interested, and then get them to put the idea to the manufactures and dealers, that way if enough people want it, then the manufactures will no doubt incorporate it.
If I have understood it correctly, would you let me know, as I can then suggest the idea to Wersi, (Being a software instrument means it would be easy to add) and also post the idea on other forums I am a member of, to see if I can stir up some interest and make manufactures take notice.
Hope this helps.

Bill