Do you know of a market for direct RC delegations? If not do you know someone planning to build such an app?

I don't know if there's any.

Is there an easy way to convert the RC costs we get from rc_api.get_rc_stats into actual Hive or USD prices? I mean how much equivalent hive power do you need to do a transaction every 5 days.

1 HP = VEST = RC // In other words, 1 HP's worth in VEST is also it's worth in RC.

If there isn't an easy way, is someone tracking or publishing daily averages of transaction prices in Hive Power or USD equivalent?

No.