I think that a DIY version of the SuperCloset would be a nice choice. You can get standing tool closets at any department store, either plastic or particleboard. Some weatherstripping and a 4" hole saw will get you well on your way.

A 2-chambered system is ideal for keeping a mother and clones alive while you flower in the large section. Keep the mother section on the bottom, because of the heat generated by your lamp, and expect to run an air-cooled hood or 'cooltube' in the flower chamber.

Those pre-fab systems are expensive but make great models to copy from. Don't skimp on the blower for your flower chamber exhaust! This, more than anything else, will make or break yoru grow.