strin6w1z4rd

The prices of z77 boards have gone through the roof.  I was forced to go with an ecs board because of how expensive they are.  Since you dont have an unlocked cpu,  maybe get an h77 board instead. 

I have one but it's running in my secondary system, if you had posted this a few months ago and I had seen it you could have bought mine reasonably cheap. They hold their value pretty well though so you would be looking at an easy $240+ on ebay. Try looking on r/hardwareswap for them, even if there aren't any listed maybe someone there could point you to someone who has one.

all Z77 boards have USB3.0 and RAID0, and most have 2 PCI-E and SLi except mITX, so really if thats what you need any old Z77 board will do

There aren't many others supporting SLI, I have a Z170M by Asus, but it only supports Crossfire.
 
You have the Z170 Maximus VIII Gene, the Asrock Z170M Extreme4 and the Gigabyte GA-Z170MX Gaming 5 as options.

Hello @strin6w1z4rd , you have definitely posted in the correct segment of the forum  
Unfortunately the majority of Intel's higher/mid tier processors utilise 20 PCI-E lanes but thankfully they're all Gen 3.0 with that said any motherboard vendor manufacturing/supporting the LGA 1151 will split the 20 lanes 8* by 8* for either Crossfire or SLI configurations.
 
Best guess is to choose from;
Asus's MAXIMUS VIII GENE
Z170M-E D3
Z170M-PLUS
Gigabyte's GA-Z170MX-Gaming 5
 
Couldn't really find an M-ATX form factor motherboard from MSI which is pretty unusual since they did produce great small form factor motherboards.
Regarding how much you want to spend is up to you but I will inform you that there are some motherboards with support for DDR3(L) specifically so you can save yourself so money instead of investing in a newer more expensive product such as DDR4 unless you feel like the cost is necessary.