Although the Z5 is pretty wide, I shoot a lot of tight spaces and really miss a good wide angle lens. There are a number of converters out there but wondering if anyone is using one and what do they think of it.

me too!?

actually i've found wide on the z5 pretty good so far, but there's been a couple of occasions where i wouldn't have minded a little more.

that said, it'd have to be zoom through for run and gun.

When the Z5 came out I was jazzed by the low light, but when I read about the G lens I was even more excited. It's one of the best features of the cam IMO. There have been only a few times when I really could have used a W/A lens. Otherwise, these show up on the B&H site:
Sony HVR-Z5U Professional HDV Camcorder HVR-Z5U B&H Photo Video

There's plenty around but I'm interested if anyone has bought and used one.

There is one here also which is zoom through
16x9 Inc. 169-HDWC75XZ5 0.75x Wide Angle 169-HDWC75X-Z5 B&H

The best thing about a good wide is that you can go super close with lots of DOF, as well as getting in lots of peripheral stuff. The more I use the Z5 the more I would like to include a WA in the kit.

After doing a test field shoot for a natural environments/landscape web video we found we needed a wide angle to really capture big spaces. we went with the Sony Wide Angle/Matte Box Kit Z5
VCL-HG0872K which has been fantastic - we leave it on all the time. You can zoom right through, and with careful use of the nd filters you can get nice shallow DOF in a good light. We often use this technique to film flowers and plants (leaves, buds, stems etc) to pull the point of interest forward out of the background.

As i said the wide angle and matte box permanently live on the camera (we purchsed a tiffen 6x4 filter as well) and the whole unit (camera and lens) fits easily into our Petrol backpack, with plenty of room to spare for headphones, wireless mics, batteries, rotolight interview kit, tapes, lcd shade etc.

I am a keen user of the Sigma DP1 - with a wide prime angle lens and so am quite happy to physically use the legs rather than the lens.