SSIS Performance Question For Custom Components

I have a SQL Server 2005 Package (32 bit, 4 processors/16 GB of RAM, 3 GB switch for SSIS) with 1 DataFlow and 5 Custom Components:

> An OLEDB Source that reads a stoed proc from Sybase
> 3 Transform Components that perform: 6-required fields check, 4-lookups (3 cached, 1 non-cached), and a calculation that is performed(called) from a .NET Library.
> A SQL Destination that uses the .NET BulkCopy Class to insert the data.

It takes about 3 hours to load 1 million records that contain 46 columns (the largest being a varchar(100)). I have tried a good number of tuning options as well as indexing/SQL techniques to improve perfromance.

Some pieces of info:
1) We dynamically create the buffer during runtime based on an SSIS variable.
2) The actions of the components are determined at runtime through config files.
We do these two things so we can have multiple data flows run through the same package for better scalability and flexibility. Since we are dynamically creating the buffer I can NOT use any of the out of the box components because of lineage and metadata inconsistency issues.

3) I noticed on PerfMon that I am spooling buffers to disk after 100K rows.
I realize this is bad, but what are my alternatives?
Should I go to 64 bit? Is there anything else I can do?

Thanks in advance,
Anthony