Both ways are hard to pull off, but are worth it if your are strapped for cash. Getting a partner is a good idea if done correctly. They need to compliment your skills and attributes, have integrity, share your goals and motivation, and in your case, be willing to risk their money for the investment.
Starting a partnership should not be done lightly, if there are cracks in the union it could pose a lot of problems down the road, especially when you hit a bump in the road. Don't let this deter you though, If done correctly, your work load will hopefully be halved and it would be easier to scale up as you will now have cash for your investments. Just keep in mind, if you enter into a partnership you also have to give away a piece of the cake at the end of the day. But half a cake is better then no cake at all.
Another note on banks and LTV, you can still get higher than 80% LTV using the seller as a second position. It's not conventional, but that's why it's called creative financing. Banks that sell to Freddie Mac and Fannie May will not allow this. Talk to your local banks and credit unions. They will give you better rates, keep the loan on their books, and be more willing to go higher than 80% LTV. Let them know ahead of time, so you don't waste your time and theirs.
Good luck!