Is there a way to show all Windows 8 Modern UI search results on one page?

Solution 1:

No, there isn't. Recall the blog post for designing search on the Start Screen:

Searching via the Start menu has continued to evolve with each release. The Windows 8 Start search experience builds on top of search features available in Windows 7 and provides a unique view for each of the three system groups - Apps, Settings and Files. These search result views are a natural progression from the Windows 7 groups and are easily accessible from anywhere in the operating system via the Search charm or keyboard shortcuts. Separating the search results into views means we can tailor the experience for each data type. For example, the File search view provides you with filters and search suggestions while typing to quickly complete your query.

Which basically means that the all-at-once search results view from Windows 7 is gone. Your only option now appears to be to think of what you're searching for and using the right shortcut. The shortcuts are as follows:

• Win(+Q) – Search for apps
• Win+W – Search for settings
• Win+F    – Search for files

As for finding a 3rd-party program that aggregates the search results again: I consider it unlikely, mostly because Microsoft has been very restrictive of allowing 3rd-party access to APIs that could dramatically alter the user experience (for better or worse – because, frankly, the overwhelming majority of programs would just take a turn for the worse). This has been the case with things like “Pin to Start Menu” or “Pin to Task bar” and creating an own search provider that overrides the default search falls very much in the realm of “unwanted and impossible” in my opinion.