Web Designer needed for as needed changes for web pages

I'm a serial entrepreneur who is looking for a part-time/daily available web designer.

We will need the designer for one month paid trial that would be extended as needed for additional months.

A little bit about us:
We are a lean and marketing focused ecommerce company based near Austin, TX. Our team is made up of some of the best internet marketing professionals in the industry. Currently, we have 7 people on our team and several more as support capacity. I have put together this team to focus on selling products in very specific niches where we have lots of experience from our prior ventures. We are looking to grow our team and add web developers and designers so our web pages can be created and changed quickly.

Here are a few of the companies I have started:
www.altitudeshoes.com
www.higherclick.com
www.sportsfoodco.com

About this position:
We need a designer for ongoing design changes, NOT a specific project that needs designing. We are not going to ask you to build one webpage and stop working. This is about taking design elements, implementing them and then making changes to find the optimal page structure for our customers. You will be implementing the design changes that our team is looking for and helping them construct user friendly web pages that will go to web developers for coding. The one month trial will be a learning experience and training opportunity in our specific niche. If all goes well, we will extend the position.

Your time commitment for this project will be around 1-4 hours per day depending upon what needs to be accomplished.