I don't know anyone doing that, but here are some questions:

1. Does the company provide leads?
2. Is your territory protected?
3. How are you at making cold calls?
4. Key markets would include elderly (my mom has one that also connects to her emergency bracelet if she falls), as well as the folks who have money in this economy. Who would that be?
5. Can you sell to a contractor in bulk, as in someone who is building some homes? Make a deal and make less per unit, but more overall.
6. Does the company provide comprehensive training? What kind of company is it; do they pay their bills or are they a "fly by night" quick buck kind of company.
7. Will you sell the system and the monthly service? If only the system, who services it?
8. What's your competition? Pricing, market share, features, etc. Figure out why you're better in advance.
9. Are you selling to businesses or residential or both?

That's all I can think of for now. Direct sales is tough, especially in this economy. I wish you luck!