Among the Core classes, Search is a class skill for only Rogue and Ranger. Its cross-class for everyone else.
Search isn't that powerful without a Trapfinding. Secret doors, hidden compartments, items in a pile, that sort of thing. If you want to burn a feat to be able to search for things, that sounds fine to me. You still have to invest skill ranks in it.
I didn't want to make Trapfinding the prerequisite for Machinist because you can use the Disable Device to do other things (although the skill is rarely used for those things in my experience.) So instead of Trapfinding I used Nimble Fingers as the prerequisite. In my opinion, Disable Device is more powerful than Search so Machinist needs a feat as a prerequisite, while Close Inspection does not.
I'm leery of giving out class skills as well. Some class skills are better suited for "giving out by feats" than others, for example Knowledge skills. I think some others would never be given out, such as Use Magic Device or Spellcraft. There are precedents for some skills being given out as class skills on a one feat-for-one skill basis: Hide, Move Silently, Listen, Intimidate, Balance, Gather Info, Survival, Heal, and Disguise (Draconic Heritage from Complete Arcane.)
I think the Rogue can be more than a trap-finder (face man, assassin, knowledge guy, acrobat) but often gets pigeon-holed as trapfinder because they are the only core class with access to the necessary abilities and skills. These feats would help out with this pigeon-holing by giving other classes the ability to find traps, if they invest a few feats.
A few sample Human characters, each with Dexterity and Intelligence 10:
Rogue 6
Feats: Nimble Fingers plus 3 feats and Rogue Class features
Skills: Disable Device +11, Search +9, plus 54 Rogue skill points
Ranger 6
Feats: H Nimble Fingers, 1 Trapfinding, plus 2 feats and Track, Endurance, Combat Style and Ranger class features
Skills: Search +9, Disable Device +6, plus 37 Ranger skill points
Rogue 2 / Fighter 4
Feats: H Nimble Fingers, 3 Close Inspection, 6 Machinist (plus 1 feat and 3 Fighter bonus feats)
Skills: Disable Device +9, Search +8, plus 30 Rogue skill points
Fighter 6
Feats: H Nimble Fingers, 1 Trapfinding (plus 2 feats and 4 Fighter bonus feats)
Skills: Search +4, Disable Device +6, plus 2 Fighter skill points
Then level them up a bit.
Rogue 12
Feats: Nimble Fingers plus 5 feats and Rogue class features
Skills: Disable Device +17, Search +15, plus 102 Rogue skill points
Ranger 12
Feats: H Nimble Fingers, 1 Trapfinding, 9 Machinist plus 3 feats and Track, Endurance, Combat Style, other Ranger class features
Skills: Search +15, Disable Device +11, plus 64 Ranger skill points
Rogue 2 / Fighter 10
Feats: H Nimble Fingers, 3 Close Inspection, 6 Machinist (plus 3 feats and 6 Fighter bonus feats)
Skills: Disable Device +15, Search +14, plus 30 Rogue skill points
Fighter 12
Feats: H Nimble Fingers, 1 Trapfinding, 9 Machinist, 12 Close Inspection (plus 2 feats and 7 Fighter bonus feats)
Skills: Search +7, Disable Device +11, plus 2 Fighter skill points
I think my calculations are correct but it wouldn't surprise me if I was off by a point or two here and there. I think these characters look OK. The straight Fighter isn't going to be finding many traps and the straight Ranger isn't going to be able to disable many.
Given Machinist's and Close Inspection's prerequisites, the best way to qualify for them appears to be to take 2 levels of rogue in order to get 5 ranks in both Search and Disable Device - this also gives you the benefit of Trapfinding without having to take the feat. The Rogue 2 / Fighter 10 is almost as good as the pure rogue at Search / Disable Device but he doesn't have many other skills but does have a lot of Fighter bonus feats to play with. The straight Rogue 12 has a lot of skill points, feats, and class features to play with - he remains the best at his role but doesn't have the number of feats, bab, or hit points of the Rogue 2 / Fighter 10.