Update:
With Data Trails out, the Agent Cluster can be realized a lot cheaper:
Now you need:
Base:
1x EvoTech Himitsu with a rating 5 Sleaze (11.000 NY)
1x Agent 6 (12.000 NY)
1x Program Carrier: Virtual Machine (900 NY)
1x Device Modification: Add a Module (2 Parts)
1x Stealth Cyberprogram (250 NY)
6x Nixdorf Sekretär (24.000 NY)
6x Add a Matrix Attribute: Stealth (48 Parts)
Parts cost: 10.000 NY
Total cost: 58.150 NY
+10 Karma if you want the Agent 6 as a starting character.
If you want an attack option, you'll have to invest in a bunch of dongles:
6x Rating 1 Attack (18.000 NY)
1x Rating 3 Attack (27.000 NY)
1x Cyberprogram Decryption (250 NY)
New total: 93.300 NY
What a brave new world

Edit: Some more details:
Every Agent 3 provides through teamwork pretty reliably (91%) at least 1 bonus die and +1 to the relevant limit.
That allows the Agent 6 to work with 18 dice and a nearly uncapped limit for all but the best rolls.
A weakpoint is the susceptibility to matrix damage and the low firewall. But without dumpshock there is no problem with just hitting restart.