As of...2? weeks ago I was told they had HipTix Gold available. A phone call is the easiest way to find out - I've never had more pleasant customer service experiences than I've had with Roundabout.
I looked the other day and I was still able to login and see gold seats for each performance I checked. Is there a particular one you're having a hard time finding?
The entire mezzanine, side orchestra, and the boxes are eligible for Hiptix Gold, so unless those sections are entirely sold out there should be availability. As stated above you have to put the promo code in first.
Do you mean there is no box to put in the 'appeal code'? I've had that happen to me before when the site glitched on me and the box just disappeared altogether. Try clearing your cookies and logging in again or using a different browser.