This Total wood chipper from PC Staal is claimed to solve the problem of variable-quality woodchip (particularly twigs and overlarge chunks) blocking feed systems by forcing the chips through a sieve to keep their size uniform.
That means that, unlike a lot of woodchip, it won't bridge at the top of the auger and should feed pretty much like more-expensive compressed-sawdust pellets.
A tractor of 70-120hp is needed and the chipper can cope with wood diameters up to 27cm (10in). Cost in Denmark is £12,900 and Staal sells in the UK via M-Trac.