CALPA tried to shove one of these "farm club" deals down Air Canada's throat a couple of years ago, the AC pilots left CALPA and went inhouse to form ACPA. Don't think it will work at Delta...
It's been tried before at American, and Continental has some sort of flow through agreement with Continental Express.
Ironically, some of the Delta mainline pilots got their seniority through their date of hire at Ransome, a commuter that Pan Am bought before it went out of business. ALPA put the Ransome pilots on the Pan Am seniority list before the shutdown, put them on the A-scale and fenced them out of the F/E seat ahead of pilots hired by Pan Am.