Hi Sam
1. Hareesh's reply above shows that there is an upgrade path from 7.0 to 7.4
2. AFAIK, all new licensing are CPU based. For licensing issues, you need to speak to your SAP account manager/executive as licensing are always customer specific. Don't think anyone can advise you in this forum that will be exactly applicable to your organisation.
3. 7.4 is the latest NW platform. Haven't seen 7.41 out yet
SAP NetWeaver 7.4 – SAP Help Portal Page
4. If you go for dual stack, it still has ABAP stack to support ccBPM
Additionally, if you are going for the "fresh install and migrate" option, for Integration Directory objects, you can use the Directory Migration tool. Although the title of the articles mentions "dual stack to single stack", it actually means from "classical scenario to ICO". As ICO is also available in 7.4 dual stack, you can consider migrating the non-ccBPM interfaces to ICOs to take advantage of the Java only processing. The tool supports migrating all the way back from XI3.0. Read the comments to get a better picture of the tool too.
Moving Integration Directory Artifacts from dual stack to single stack
SAP Directory Content Migration Tool
Rgds
Eng Swee