If you want to try to predict who will be adding D1 next, there are 2 options, in my opinion.
1) Large school, big money donors, edge to a private school, but a big public works too. Likely a Power 5 conference school, with some kind of tenuous hockey connection already (in a successful NHL town, well known hockey-enthusiast uber-rich alum, etc.) Schools that already have ice capabilities in a large basketball arena would have a lower "cost-of-entry" and require less big money donations. Examples: Illinois, Northwestern, USC. Goal would be to join the BIG or NCHC.
2) Smaller school in a hockey hotbed. Likely already has a D3 program*, and makes the jump (despite the lack of scholarship issue), because they want to play with the big boys. Cost of entry is much lower, because infrastructure is there, and likely destination is a league like Atlantic Hockey, or maybe the WCHA, not a Hockey East, BIG or NCHC. This is less likely, IMO, with the exception of I would expect some east coast D3 schools would be able to make the jump to Atlantic Hockey without too much additional effort. Sure, it would be a bigger investment, but infrastructure-wise, they would be ok.
*Caveat: A school that is D3, but going D1 in all sports would be a very good bet. Specifically, a UW system school could theoretically be in this situation.