To the companies who are trying to build walls and dig trenches around marketplaces which serve this end, personally I hope they all fail, and we end up with a distributed network which can host the necessary ledgers and market-making functions required.
If anyone here has the legal chops to help build this, please email me ;-) I've done my own 506(b) and I could build the distributed trading engine (did similar work on colored coins) and I would love to open source and democratize a platform for this.
I look at what SolarCity did with SolarBonds, which is a platform built by Common Assets who they acquired (unknown amount), if you've tried that platform, I think you have a taste of how SME companies could sell their equity.
I think the right platform can also significantly reduce the burden of an extremely long-tail cap table.
From a fund / roll-up perspective, the companies host their own trading platform, there's no reason the funds can't buy shares right on there, bundle, and resell the mix to their LPs. Someone like FounderFund benefits by being able to cheaply (as in transaction fees) acquire equity in many company who are running the A+ platform.