But trying to convince my investors that this was a great time to buy homes, fix them up, hold them as rentals and resell them in five years under the thesis that prices would double was a nearly impossible feat. 

It's hard (albeit not impossible) to finance all of the purchase on an apartment.

Not impossible but challenging to find the right deal.

Getting one approved is laborious at best, if not impossible for an average homeowner.

But @Arlen Chou I thought it was impossible to find cash flowing properties in the Bay Area?

If you have good attic access and can put up a radiant barrier easily (I have a super low pitch roof so this was near impossible), that is also probably cheaper than insulation.Attic fans work well in perfectly sealed houses. 

Hence why it has been impossible for me to sign anyone a month before school started.

One of the things that's impossible for anyone here to factor in is how much we like the property and the setting.

The IRR is the definitive metric, and it's very difficult to make things work (I'd say impossible), with anything less than at the absolute minimum $250 per door value-add.

Right now the most I can think of would be trying to get a HELOC, but I've heard many people say its impossible to get a HELOC in that range.