For developers who are looking to get paid more frequently from mobile advertising networks, Velti’s Mobclix is providing cash advances on a two- and four-week basis for a fee.

The company is launching an advanced ad payment program, which lets developers get paid every 15 or 30 days instead of waiting for as long as three months.

The advances come at a cost, naturally. If a developer chooses the 15-day version of the program, they must pay a fee of 10 percent of all monthly revenues earned. If they pick the 30-day version, the fee drops to about 8 percent. This is not a one-time fee. It’s a recurring percentage of monthly earnings. Consider it like a traditional cash advance program on pay checks, which come with steep interest rates.

“The reason there are fees is two-fold: developers get money faster, but, in addition to the cost of borrowing money, it requires engineering and finance effort for the company to maintain, so there is a fee for this service,” a Mobclix spokesperson tells us.

Mobclix is a mediation network that swaps in the highest-paying ads into an app from multiple mobile ad networks. That lets developers have higher eCPMS (or higher revenues for every time they deliver a thousand impressions of an ad to consumers). The company was bought by Velti in 2010 for $1.1 million in cash and $1.4 million in stock. But the company’s founders and employees could get up to $43 million in earnouts this year if they meet certain revenue targets. A cash advance program, provided there are enough mobile developers who need liquidity now, could be a smart way to get there.