Are there any chengyu or xiehouyu that only mean their literal meaning?
I think all chengyus should have their figurative meanings. 

xiehouyu  usually has two kinds: 


  
  逻辑推理式 // logical type, For example, 哑巴吃黄连, 有苦说不出.
  谐音 // homophony, For example, 外甥打灯笼, 照旧(舅)
  


泥菩萨过河 should fall into logical type. So, there are lots of that type if you go Baidu. 

Couple of links for your reference:


  逻辑推理式
  
  谐音