Skills such as list, documents, workflow, permissions... are a bit too basic and are requirement for a SharePoint DEVELOPER.
I'd argue that perhaps site (and site structure) is an area that would fall under the architect's plate.
There are more areas that a SharePoint architect can help with:
- Capacity planning - running multiple servers in a farm.  Scalability and other magic words. 
- Knowing the capabilities and business scenarios of using SharePoint - this is a very common one.
 The manager asks: what can SharePoint do for me?
The developer asks: well, what do you want it to do.
The manager then asks: well, I don't know what it can do for me so how do I know what do I want it to do?
 
- Closely related to SharePoint capabilities are the various licensing costs related to each component. 
- As well as familiarity with development and customization costs.  Take the same project time that would have taken in ASP.NET, then multiply it by a large coefficient, and then add an additional constant. 
- And closely related to what-can-it-do, and how-much-does-it-cost, is the all important question of Return-Of-Investment.  All hail supreme ROI! 
- SharePoint deployment can be a massive issue and a lot of pain. 
- SharePoint upgrade from v2 (MOSS 2003) to v3 (MOSS 2007).  We should be seeing a new version of SharePoint in 2010(?).  Well soon after the next version of Office goes out the door.  So past upgrade experiences may be useful. 
- Knowledge of 3rd party webparts.  I believe a SharePoint architect should be able to give you at least 5 webparts that they've tried from CodePlex and tell you what they think about them.  These are free and easy to grab and play at your own leisure. 
- Some knowledge of commercial webparts.  Because they are still cheaper than writing your own. 
- Have at least 5 SharePoint blogs that they follow religiously (know the community).  If not having their own SharePoint blog (give back to the community). 
- If they are on StackOverflow they must try to answer SharePoint questions (such as this one). 
- Attend local SharePoint usergroups.  I think communities are a huge deal.  Especially what you'd learn from talking with people directly and learning what they are doing with their SharePoint installation.  You may just surprise yourself. 
- Experiences with SharePoint Integration - this comes in two equally important flavours - both from SharePoint accessing existing systems (business catalogs, webparts, etc), as well as other systems accessing SharePoint content via webservice or API. 
- In addition, SharePoint works with (or works well) with Office, OCS, reporting services, performance point, project server. 
- SharePoint hosting arrangements - Microsoft SharePoint online services can be a popular and cheaper option to start using SharePoint.  It can be hosted inhouse, or with a 3rd party company.  Knowing the options is always useful. 
- Must have read SharePoint code using reflector (and preferably still having hair). 
I think it takes at least a couple of years to be a SharePoint architect (your mileage may differ).  Your .NET architects need to want-to-be a SharePoint architect, otherwise I agree with other's summaries before me - find someone who already is a SharePoint architect.