Gelato 2.1
Nvidea's Gelato render is free. We've worked with them on a shave interface, it operates much like our MR integration.

Floating Licenses
Shave is now available in a wide variety of sizes and flavors with different sizes of floating license packages. The licenses will float across any LAN and even to multiple platform targets (win32, win64,OSX risc, OSX intel,Linux32,Linux64).

Mental Ray ships with Maya.
We've produced a space partitioned geometry shader which runs native inside Mental Ray. You just run your renders as usual. It generates Mental Ray Hair Primitives on demand and shades them. We also have an export command for .mi files for standalone rendering.

PRMAN / Renderman Studio
Pixar's PRMAN is an integral part of many high end pipelines, with Shave, you can generate space partitioned RIB's directly - this means no memory restrictions on haircount limits. We also apply this feature to our 'instancing' object generation, so you can render millions of anything (trees, feathers, etc).

Because we generate hair as local Delayed Rib Archives, you can use it with all versions of prman since 3.1, and most workalikes.

Adding dynamic hair to your RIB becomes as simple as adding one line of text.

Because we use delayed read archives, the implementation works with a host of other renders like Air, 3Delight, Pixie, RdotC, and more, so even if you can't afford Prman ,there are similar options. We include source to our surface shader (shave.sl) so you can recompile our shader for any prman render.

SDK
Shave provides a front end that even newbies can use, but goes a big step deeper and provides development tools at the Mel level and at the C++ level that will let you glue it into any Maya based pipeline you can conceive of and even write plugins that communicate with the Shave engine.