I think that the butcher shop on Nairn (Sausage Makers?)sells rabbit as well, but as with the other stores, you need to order in advance. At least I recall seeing a sign declaring so. There's also a new butcher shop in Transcona on Regent (Al's Meats) that has the same deal.
Harborside Farms carries it, but I don't know how often they have it. You'd have to place your order online and pick it up at the pick-up point closest to you (they deliver to Winnipeg twice a month). The other option is to visit their store in Pilot Mound (hours on the website), but I'd call first to make sure they have some rabbit.
If you do order from them, ask them when the rabbit was processed and how long it has been frozen (if at all). I've ordered meats from them only to find they had been frozen one month earlier. That wouldn't be so bad had the meats been vacuum packed, but they were wrapped in butcher paper (which definitely does not prevent freezer burn).
ETA: I don't know if you asked at any of those shops, but sometimes, even if they don't have any in the display cases, they may be willing to order some in for you. I also vaguely recall seem some rabbit in a freezer somewhere recently. Will get back to you if I remember.