Looking for Aftermarket Electric brake booster for '96 truck

I'm looking for an aftermarket system that will replace the current master cylinder/brake booster for a 1996 Chevy 1/2 ton truck that uses electricity instead of vacuum. My brakes are spongy, I've already bled the brakes, checked the rear drums for proper adjustment. The master cylinder, brake booster was recently changed in the last 4 months or so.
I know someone makes one of these electric units, I just don't remember who it is. I've done internet searches and can't locate them, maybe in CA? I'd talked to the business a few months back when the problem started, just didn't want to spend the extra bucks. Now I'm ready as the problem is back. :banghead:

The brake booster wouldn't make the pedal feel spongy, it would make it hard.

Changing out the master cylinder and booster is not going to fix your problem. if the pedal feels spongy then it is possible that you still have air in the lines. Brakes have to be bled in a certain order to make sure that all the air gets out of the lines. Going to an electric master cylinder and booster is just going to mask the problem , kinda like using elastic bands for sagging springs.

A deteriorating rear brake line can also cause the brakes to feel spongy. When you hit the brakes, the line expands which feels the same as air in the lines. If you find the line is deteriorating, replace it immediately.

The order for bleeding the brakes if furthest from the master cylinder to the closest. Do the right rear, left rear, right front and then left front.

Also, when you installed the master cylinder did you bench bleed it first? If not, you may have torn the seals, which means you will have to replace/rebuild it again.