Lightening web page load for crawlers

On a shared host, I'm experiencing high CPU / page load times. Wincachegrind and Firebug showed that the bottlenecks are:

- db queries (time)
- images loading (time)
- Wordpress plugins / filters (CPU)

I have installed WP Supecache, however I have noticed that the problem has been shifted elsewhere: as the site has a great numbe开发者_StackOverflowr of posts (> 50,000) the time & CPU consuming task has been shifted to WP Supercache generating static files, on crawlers access.

Ironically, the site has very little user access daily (about 1,000), while suffering large crawler access daily (Google webmasters shows a MAX:23,669/Average:11,712/MIN:4,069 pages stats).

I was thinking about helping the crawling page phase, avoiding loading some elements/parts of the page when being crawled. For example, images and "related posts", not "strategic" for the indexing process....could "lazy loading" of those parts help?

Or? What steps would you take further on, assuming:

- the users traffic to the site is very small, 
  not justifying stepping to costly dedicated/CDN solutions
- Efforts have been taken to minimize plugin impact
- Page design has been improved using CSS sprites, source minifying, 
  using consistent host names, etc, etc pushing page score 
  to higher limits (Yslow, pagespeed)

I believe the next step would be to use Wordpress as the backend, creating a lower level coded frontend (PHP + MYSQL)....

Comments appreciated

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I have switched to a dynamic page whose content is loaded with jQuery. This turned down page load time to a 1/3 !!! Great!