This is great - definitely one of the biggest challenges facing the ROM chef community has been Google's limitations on the Android Marketplace app. Even companies like SlideMe.org put the burden of licensing their market app on the product manufacturer.
All of this drives up the price of what could essentially be cheap tablet pcs with Android, as only established brand-name electronics companies are able to meet these rigid guidelines established by Google. And until Android tablets are supported by the current version of Android - currently v2.2 ("Froyo") restricts screen size and resolution among other requirements that are not ideal for an Android tablet that could compete with the iPad.
With cell phones, the wireless carriers add to the pressure to keep handset prices high, as they use steep discounts to lock in 2 year contracts; a business model that limits selection in the consumer market, particularly for the most reliable carriers, and virtually eliminates the ability for any non-affiliated handsets to enter the market.
It's also difficult for OEM manufacturers to develop products for mass cell markets because of varying frequencies and bandwidths in each country.
Tablets, on the otherhand, essentially provide non-cellular functionality such as connecting to the internet and playing games - and perhaps provide one of the most exciting opportunities for the open source ROM and app developer communities to make some money on the sale of hardware devices rather than putting their efforts into unlocking (or improving) hardware made by major brands.
These should serve as a good starting point for starting to source out good cheap android developer tablets: http://www.androidgold.com (we're reviewing more every day). These expect to release these for sale on October 1st or sooner.
We're reaching out to the ROM chef and app market communities who want to work directly with small OEM manufacturers in China ideally with profit-sharing arrangements that compensate the developers for the Android tablets and phones we source and develop with our manufacturing partners.