Best I can come up with is:
1♠ - 2♣
2♠ - 3♥
4♣ - 4♥
6♣
Is this realistic? It requires to North make some prescient assumptions. First, the awesome 4♣ bid assumes:
- 3♥ was not an attempt to get to 3NT looking for a Diamond stopper
- we are giving up on spades as trumps (as 2♠ only promised 5) ... unless of course a 4♠ bid by South is passable. (I don't think it is .. is it?)
Then, after hearing about the 6-5 and realizing he may have the magic hand, the raise to 6♣ still assumes partner has no wasted values (like a stiff spade honor) and a one loser Heart suit opposite 10x.
Some of these 2/1 auctions drive me crazy. Do you think you would get to 6♣?