Andrew, I see no one has responded to your post! I'll give it a shot here to see if I can shed some light on the subject.
Most investors avoid going conventional because it's expensive, time consuming and eats up quite a bit of your cash, now that we have to bring in 20% down before they'll even consider looking at the loan. Many lenders also put a cap on the number of properties you can have as a criteria for lending to you. If you currently have 12-properties with a mortgage on each, you will be hard pressed to find a bank to lend on your 13th property.
You may also consider a hard money lender. These are individuals or companies that loan to real estate investors. The loans are usually short term (say 3-months to a year) and are expensive, however if you have a smokin' deal you need to close on quickly, this might be an avenue to consider. The loans usually include a hefty chunk of points up front and a high interest rate. However, if you crunch the numbers, sometimes you're better off with a HML because you're only borrowing the money short term.
As for private money lenders, they are all around you. It could be your parents, your barber, your next door neighbor, the clerk at the grocery store, your accountant, dentist and so on. The key is to tell everyone you know that you are an investor. You ask them if they know of anyone that isn't making at least a 10% return on their investments (IRA's, CD's, savings accounts, etc.) that is totally secure and would like to do so. Most of these people are not making close to that kind of return. You will be surprised how many of them will want to know more (for themselves).
Once you snag a few of these people, and you deliver exactly what you say you're going to deliver, they'll tell their friends about you and their good fortune. People like to boast about their good decisions, especially when it comes to making a nice return on their money.
Once you have a list of people willing to invest, you can send out your investment proposals. Let's say you've snagged an $80,000 property that needs $10,000 in repairs. You need to raise $90,000 total. Send out your property "prospectus" to your list of interested investors and let them know they can buy in at $5,000 per share at an 8% return or $10,000 per share at a 10% return. If you get 9 people wanting to invest $10k, you've got your $90k. If you get 18 people wanting to invest $5k, you've got your $90k.
Please note that when you do this, there are specific guidelines you need to follow so as not to have the SEC or the IRS come calling. Your attorney and accountant can walk you through what you need to do to set this up properly.
There are countless books, written by many a guru that you can get from the library and can give you some insights as to how to finance your deals.
Hope this helps and let us know how it goes!