Reviving a dead thread because it's late at night and I'm waiting for SSIS to finish running. For me the difference between SQL Developer, Architect 1, DBA, and Architect 2 is in your duties and skill-sets.

SQL Developer: Creating the tables, views, stored procedures, indexing, etc, to support the back-end of an application.

Architect 1: Akin to a Business Analyst, they sit in boring meetings and write down the vague requirements from a business, and turn them into magical conceptual models (tables, relationships, etc) as well as ways for applications to interact with those models (XML schemas and .NET classes, etc). They then farm out some of the database-side work to the SQL Developer and DBA accordingly.

DBA: Operations. Keeping the databases up and running and healthy. Doing the setup, backups, restores, maintenance, instance upgrades, rolling out database schema upgrades to PROD, finding problems which affect the entire server fleet, general performance tuning, and higher-level functions like compression, in-memory tables, etc.

Architect 2: Putting together ideas for how a data centre of SQL Servers should be built up; from the hardware (SANs, CPU, RAM, SSDs etc), to software (server OS, clustering, AlwaysOn, etc), to configuration (archiving event logs, offsite backup locations, etc). Much of this is then farmed out to the DBA afterwards.

I've been in the SQL Developer role and (currently) DBA role. But I think moving into either Architectural role legitimately is a pretty tall order.