For a development enviroment I would say you could do this within reason.
Keeping separate application pools would be advisable. Use at least a 4 GIG machine.
Also keep your SQL server on another machine.
I would not recommend this for a production environment.
Consider all the indexing in Share Point and the work that the application layer of CRM has to do , you would be hurting yourself and impeding the adoption of both packages.
Curtis J Spanburgh