And, even then, they might not offer the product to foreigners.If you have a high account balance in the US, your HSBC US might give you a personal loan against your cash as collateral or HSBC UAE might give you one - if they offer that product (to foreigners) - against a guarantee from HSBC US, which would be back by your cash being held by HSBC US as collateral. 

If your property appreciates, you build up equity, your leverage decreases and consequently, your return on equity too; when some properties have greatly appreciated it may be time to do a cash out refinance or use that equity as collateral to serve as downpayment for another investment

Contact small, local banks and ask for the commercial lending department and ask if they keep loans in house, so that you can continue to purchase homes at fairly good rates, without worrying about the limit.Make sure to ask how they figure out DTI and make sure they use the rental income to offset the debtAnother option could be to use a few of the homes as collateral and try to get investment HELOC's or Line of Credit (terms aren't great though, so I generally stay away from these options). 

Do you have any assets that you can use as collateral

Collateral when you need a private money loan or hard money.  

I still might but it had a collateral effect of making the place look better.

If you have equity in those properties, you may be able to use them as collateral on a loan for the down payment on the new property.  

Ray Slack my recommendation is to have an attorney review the collateral for $250.

What's different about notes with RE as collateral is that they are (usually) secured by a mortgage or deed of trust.

Columbus - after receiving collateral and the deeds in our possession, the property was abandoned / trashed and the grass was 3 feet high.