I'd like to start offering such a service for deals and I want to build a reputation in the most unscammy way possible.
Aside from signature keys and facilitating deals of NO MORE than 0.01 BTC to start - what else can I do to start building a positive rep?

Portfolio can be viewed here:
https://dan.com/domain-seller/rumplebottom

Willing to consider trades of other domains or digital products, in-kind.