Will use a hydro roller grind with solid roller lifters.
I see guys doing that, but what it means is that the camshaft was not designed correctly in the first place.
If a hydraulic roller cam can't be used with a hydraulic lifter, then it means that the lobe was too aggressive, the valvetrain was too heavy, or a combination of both. FE's have some of the heaviest valvetrains of any engine family and it takes a certain combination of parts to get them to work easily. When you get the right combination of cam lobes, lifters, spring loads, etc., then it's very easy to hit 7000-7500 rpm with them.
If the goal is to use a very aggressive lobe to make more power, then by all means do it, but why not just use a lobe that's specifically designed for a solid roller application? There's a risk involved with running solid roller lifters on the street. If that risk is going to be taken on a 5500-6000 rpm engine, then I don't see the need in specifying a "hydraulic roller" camshaft. A hydraulic roller lobe with a solid roller lifter will still need a lot more spring load than it would have required with a hydraulic roller lifter and unless it's a "hybrid" lobe, the lash requirements will be much different as well, usually much tighter (.005-.006").