Will this work?

[flexed2death]

I currently have two WB68's and want to add a SWM8 to the mix. Can I just add additional high frequency splitters (making sure to match 13v to 13v, etc...) to the mix to connect the SWM8? If so does anyone sell a 1x3 or even 1x4 splitters? My current setup is that the output of my dish goes to four 1x2 high frequency splitters which fed the two WB68s.

[veryoldschool]

Yes it will work.
I use Skywalker splitters:
http://www.a1components.com/itemdisplayn.aspx?item=4350

[Grentz]

Another option would be to replace one WB68 with a WB616 and then add the SWM where the other WB68 was.

[rudeney]

Another option would be to replace one WB68 with a WB616 and then add the SWM where the other WB68 was.

That's exactly what I did. It was an easy plug-and-play as the original install already had all the cabling in place with 4x 2-way splitters to parallel the two WB68's. Of course I took the opportunity to clean-up the mess of cables that was on the attic floor, but otherwise, it was a no-brainer.

[flexed2death]

Thanks for confirming that this will work. I thought about switching out the WB68 with a WB616 but it's cheaper for me to just buy 4 new splitters than a new WB616.