Maybe we could do a joint venture sometime.  

One is 28 and married with a 1 year old, the other turned 15 today, and we are now investing part time under an LLC.What we've been considering so far would be to open a (joint?)

Reg D allows a company to raise unlimited funds from an unlimited number of accredited investors and up to 35 non-accredited but sophisticated investors.An accredited investor is someone with an annual income of at least $200,000 (or $300,000 if filing taxes jointly) for the last 2 calendar years, or someone with a net worth over $1 Million, excluding their primary residence.

Assuming you have a lease that has boiler plate language you should not need to create another agreement as the lease agreement already indicates that the tenants are jointly and severally liable for all terms and conditions most key of which is payment of rent.

We file taxes jointly by the way.If there is a better way, please let me know.Thank you!

Also since my wife has a W2 job should I quick claim deed it to us jointly to boost our income level?  

Trying to jointly do any deal, particularly a high-dollar deal like yours, requires serious legal support.

If you consulted a good attorney and you jointly came to the decision to create 2 LLCs then it might be the right decision. 

My lease say that tenants are jointly responsible for damages to common areas. 

She refused to file jointly before the divorce, so he filed after.