I’m also investigating using Magento to frontend Oracle. This is where I am:
Why would anyone do this?
1) Oracle is a very extensive ERP system. For medium business (500+ employees) It does suply-chain management, internal controls, ERP, accounting, quoting, etc.... things that Magento can’t do and wasn’t designed for. This is especially true if your company has already been using Oracle for a long time and has installed links to your vendor’s ERP systems.
2) Unfortunately, Oracle’s e-Business suite (namely iStore) can be very difficult to customize and looks like 1998. It’s entirely JSP based and looks like a big mess and is not SEO friendly. It’s made worse by any patches to the Oracle code may/can/will screw up your customizations.
3) The advantage that iStore has over Magento is that it’s already fully integrated into the rest of the Oracle system.
Possible solution #1
Solution: Tie Magento’s SOAP to Oracle 11i’s XML/SOAP gateway. Push orders from Magento directly into Oracle’s Order Management module.
Problems: Not exactly real time, getting customer data / orders, etc back into Magento, synchronizing Oracle’s inventory management system with Magento, integrating Oracle’s Single Sign On module with Magento’s own user management.
Possible solution #2
Solution: Create a Magento module that overwrites most of the product, inventory, and order placement, and leverages Oracle’s iStore instead.
Problem: Back to customizing Oracle so you’ll have to deal with custom/seeded code conflicts, you lose the best features Magento has to offer for e-commerce (eg: comparison shopping), it’s a lot of work, Magento themes won’t apply to Oracle, the scalability is questionable, upgrade paths for Magento and Oracle could be a enormous nightmare later.
I’m still reading and digging to find something that might work better.