If you're not switching to SharePoint 2010, you are missing a huge opportunity. The new features actually position it so that it can become the ONLY application that end users need to log into. All kinds of useful SharePoint applications can be easily built to bring data from multiple backend systems together, aligned in a single window, for user viewing and updating.
You probably don't think of SharePoint as an MDM product, either, but maybe you don't really need the multi-million-dollar, huge upkeep, of the MDM products from the (other) Big Guys.
You may know that SharePoint 2010 advanced the concept and usability of virtual data definitions from the earlier Microsoft Office SharePoint Services (MOSS) to include full CRUD (Create, Read, Update, Delete) and other features like SSO (security). This "external entity" catalog, called BDC, or Business Data Catalog, functions as an MDM of sorts that contains the metadata describing corporate business entities along with the metadata describing how to get the data and where it comes from. When a user opens a window that is bound to one of the entities, s/he can interact with the live data without knowing or caring where it came from. The interaction is with virtual data accessed live from backend systems.
SharePoint Designer is a nice tool for building the metadata when it comes from a limited range of single sources. With some amount of programming, you can extend its use a little. Unfortunately, without the ability to update an external entity's metadata definition, SharePoint Designer must create a whole new definition, which then needs to be switched out for all the apps that use it.
SharePoint 2010 really flies, though, when you combine it with an Agile Integration Software (AIS) like Enterprise Enabler http://www.enterpriseenabler.com/. Agile integration brings the ability to build complex data mappings, from multiple sources (without programming) and generate the desired external entities in SharePoint. Federating data on the fly from multiple sources is powerful.
Now, suppose the backend systems changes. Maybe your entity combines data from SAP and Dynamics CRM. If you switch from Dynamics CRM to Salesforce, an AIS can apply the changes behind the scenes to connect the same external entity definition in SharePoint without any disruption.
There are a couple of things you might be concerned about, like security and transaction rollback on updates to multiple back ends. SharePoint supports SSO, so AIS will pick up the end user security from SharePoint and pass it to the backend systems. If the user does not have permission to read from a backend system, s/he will not see the data. If the user does not have write access to one of the backends, the full transaction will be rolled back. This is generally the only time data is actually persisted in an AIS.
This should definitely give you something to think about. You could use all the savings for a company trip to Colorado, or Hawaii, or anywhere else. Or maybe give a fat raise to everyone in IT.
Video of building a SharePoint entity in AIS http://tinyurl.com/5vxce55