Y'know, the more I think of it, the more I'm thinking rash doesn't actually NEED the don't untap clause. I mean, you could have that as a downside on some of these cards if yuo wanted (e.g. maybe on a rash pinger?), but generally you don't HAVE to have it.

I would have Rash costs be alternative, rather than additional, a lá Dash. I don't see any reason for them to actually be more expensive in most cases if you're going to keep the downside. Which I would

Having them stayed tapped makes it a theme for Gruul as a whole. Makes them seem short-sighted compared to other guilds, esp. Orzhov.

Additional cost is homage to kicker. However it may be harder to parse and customize.