Info 2 SPH-L720 Galaxy S4 Rom Rival Storm V.2.1

Hello everyone,

I am new to the forum and have very little experience with ROM's, please help while you can.

I have been testing and trying many ROM for my Galaxy S4 PH-L720, a few of them I think are great and others were just not what I expected. but I have installed this ROM which I love, I think it is the most close to perfect ROM out there at least that I know of. This ROM is called
(ROM][XXUGNF1][4.4.2] S5 RivalStorm V2.1 [SLIM][S5 Apps/Features) Everything works flawlessly chi I have not been able to accomplish with any other ROM. the only disadvantage is the the Model Number is GT-I9505 and it is only CDMA enable, I would love to use this on any carrier in the US (Sprint, Verizon, Tmobile).

Question:
Is it possible to install extra Modules or a different Kernel to have this ROM also be GSM, LTE, eVDO?
Are there any ROM like this one that support these features?

I have come across a few but they are all international.

Why are the developers not creating something like this for US carrier based phones (Galaxy S4,S5)?

Thanks in advance to all.

Kalimasito