The problem with this model is that consultants will want to be paid in liquid cash, companies will want to pay in illiquid equity, and someone would have to step into the middle and establish valuations and liquidity. This is the bigger problem with the increasing illiquidity associated with VC funded startups. Savvier would-be employees or consultants risk adjusting shares even further towards the direction of worthlessness and insisting on cash.
With that said, perhaps the main silver lining I see here is of VCs playing a role in creating some kind of liquidity for shares. By establishing a three party transaction like this pegging exchange rates between hours of labor, shares and dollars, they're setting at least a stated valuation that allows companies to pay with either shares or cash to prospective employees and service providers, with the risk underwritten by the VC.