tbeezy, excellent question. Here are a few trial closes for your consideration:
1. Do you feel like we're on the right track?
2. This widget does such and such, and you said that's important to you; do you agree this widget does such and such?
3. Do you like it?
4. You said you wanted _________; do you think this widget gives you _______?
5. If this widget was free, would this be the right widget for you?
6. If we work up a price for you and the price is acceptable to you, is the route you would go?
7. When the time comes to make a purchase decision, is this the product you would choose?
8. If you decide this is the right product for you, would you feel comfortable doing business with me?
9. If you decide this is the right product for you, would you feel comfortable doing business with XYZ Corp?
10. When you started looking for widgets, is this widget close to what you had in mind?
11. How far away are we from this being an ideal solution for your needs?
12. You told me ______ was important to you. Do you think my product solves your concern?
13. Could you yourself using this widget?
14. Could you see this widget working for you in your (home / company / car / office / whatever).
15. If we can meet your delivery requirements, do you think this solution would work for you?
I hope that helps!