IMHO, Lease Purchasing is an awesome investing strategy out there but you need to have a good understanding - which means educating yourself thoroughly and having air-tight contracts.

Below are quick links to get engaged on this site.It's good to hear of your tightly coupled (no pun intended) partnership with your wife.You mentioned building a portfolio of properties and I suggest listening to podcast #151 if you haven't done so already. 

Throw in some damage, uncleanliness and a final utility bill that hasn't come through yet all in a 14-day deadline and that's a pain, too.  

The closing window is tight - usually 21 days.They will NOT allow you to assign the contract, and many impose deed restrictions barring you from reselling it of at least 3 months prohibiting an A to B to C close (double close).

Get tight with a good inspector to help you anticipate (if it's not to your liking, invoke the inspection contingency and back out of the deal). 

I like  Johanns  idea of the tightly placed granite (or cost effective tile for you). 

I see money management at the foundation of many problems with rent but I would suggest that even when funds are tight if there is an income source someone is getting paid.  

Depending on how tight the market is in your area you can, at times, get them to pay you more than what they believe the "market value" is but at times (when their money is tight) they will reduce what they will pay (and, once again, tough noogies to the landlord).We were able to increase the rent on our one Section 8 rental (when we participated in this program) by (gasp!)

With a tax lien you may have a deadline however.

I guess I'll just sit tight.