Putting aside server load / config issues, and from the pure SEO point of view.
No, you shouldn't have any major issues with that many 301s. However, what you might find is that depending on the size of your site and the frequency of Googlebots visits that some of these pages take a long time (months) to drop out of the index and be replaced by their newer alternatives. This normally isn't cause for alarm.
In some instances you might end up with pages that now have now links to them (as their parent categories were all redirected also) and so seem to get stuck and never get recrawled by Google to update. In a couple of instances I have had success using XML sitemap files that just include these 'blocked' pages (the old URLs still in the index) to prompt Google to recrawl them.
Also there is Google Webmaster Tools feature to 'crawl as Googlebot' which then prompts you to 'submit to index' which you can use to prompt recrawls on a per-page basis (but you have credits here, so should only be for the more important pages).
Best of luck!