There are better ways to store point clouds than Maya cache (as has been pointed out by previous answers), but if you are really interested in doing this, you can check this paper:
http://100cells.com/downloads/MayaCacheDLL/MayaCacheBitstreamDocumentation.pdf
There you can find a description of the Maya cache file format (obtained by reverse engineering) so you can develop your own Maya cache exporter in Houdini. I did a prototype using Python and it works. You can export any custom attributes you want but It's important that you create attributes in Houdini that are always needed for Maya:
- position
- count (special Int channel with just one point size, representing the point count)
- id (don't remember if it's mandatory)
For rendering with motion blur I think it crashes if there is no velocity channel, but it may depend on the renderer. You should open a genuine Maya cache file in an hex editor and see what channels are exported in a working cache file. Also take a look at the XML if you are doing multifile caches, as you will need to create it too (at least this is simpler than the binary cache files).
You can find a C library here:
https://github.com/100cells/Maya-Cache-DLL-Project
maybe it's not the best implementation to use in Houdini but can be usefull as a reference.