[ZTE Z7, Z7 Max, Z7 Mini] pedrud:
I think this thread is only for existing ROM's for the Z7 mini, but I will post some basic information here. Please search elsewhere on XDA for more information.

I'm not sure what you mean by a good background for going at it; however, I think having a good understanding of computers and even some basic programming is very helpful. As for myself, everything is self-taught. I'm pretty familiar with mac, PC, and linux. Even if you are completely new at it, there is lots of good information out there - I would just encourage you to start by learning from credible and well established sources. I have only tried porting for nubia Z7 mini - no other android. I previously used the iphone (and am frankly glad I now have android).

It really depends on whether you want to do a simple port (that's how I call it - don't know if there's an official way of calling it) or port from source. If you are doing a simple port, you can use any computer (mac, pc, linux); however, if you want to port/build from source it is by far the easiest to do it from Linux. There are many resources out there for building/porting from linux - most of which are using Ubuntu. I personally use Debian (which incidentally Ubuntu was created from; however, they are now each distinct and different), but you could use most any linux distro as long as you are comfortable using the command line. Also, if you are using linux, make sure you have enough hard drive space available (most recommended is at least 30GB) and have enough RAM (I have 16GB - minimum recommended is 8GB). It's also very helpful if you have a large swap set up as it makes building go faster. Once you have everything put together, compiling/building takes 3-5 hours depending on the specs of your computer. I have a 1.7ghz i5 in my computer and it is slow - 4-5 hour range for me.

For the sources list below, please note I have no affiliation with them and do not know them. Use at your own risk, I assume no responsibility for what may happen to your computer or phone.

I think some of the best (and frankly most detailed) information comes from the android source code website and from XDA-University.

https://source.android.com/index.html

http://xda-university.com/

For what I call simple porting, can be done on any computer - this was the site I started with and it seemed to work except that I kept getting boot loop issues. There are many other sites out there with nearly identical information. This person uses a PC, but you can adjust it quite simply for doing this on mac or linux too:

http://seekandroid.info/2014/05/porting-android-roms-for-your-phone.html

The following site/instructions are very interesting as they are different than any other site I found out there with porting instructions. I have not done it this way - primarily because I am concerned about "bricking" my phone. The method this person uses is the same; however, the files that they transfer are opposite to most any other site I've found. I have not used these instruction - be very cautious until someone else can confirm.

http://anythingsyouneed.blogspot.com/2014/06/how-to-port-custom-rom-rom-porting.html

This one seems interesting; however, I have not used anything on this website and have not used one of the Kitchen programs.

http://www.littlegreenrobot.co.uk/tutorials/how-to-cook-your-own-android-rom/

Android - excellent and very detailed. Personally I think most helpful to those with intermediate to advanced programming knowledge. Or at least have the ambition and time to learn.

https://source.android.com/source/building-devices.html

XDA-University - Truly amazing wealth of information, approachable for anyone from absolute beginners to advanced programers.

http://xda-university.com/as-a-developer

http://xda-university.com/as-a-developer/porting-aosp-roms-using-source-code

I've been busy and haven't had a chance to use these pages yet, but it's what I'm going to do next to try and solve the boot loop errors.

http://xda-university.com/as-a-user/zip-based-rom-tweaking

http://xda-university.com/as-a-user/how-to-recover-from-a-bootloop

If anyone has anything to add, please do. I'd be interested in seeing what else people use.