How can the ruling in Colorado v. Spring help?
Presumably, the greater a suspect's perception of the risks he is facing, the greater the odds that he will refuse to waive and answer questions. Conversely, the smaller his perception of risk, the more likely you will get a waiver.
Since Spring does not require you to put the suspect on notice of all of the more serious charges he may be facing, you can obtain a valid Miranda waiver by arresting the suspect on less serious charges, giving a warning and obtaining his agreement to talk, and then asking questions about every crime you suspect him of committing.
For example, suppose you run your murder suspect's information and learn that he has an outstanding arrest warrant for failure to appear on a traffic citation. He could be arrested on the traffic warrant and taken to the station. Without telling him that you also suspect him of the murder, you give the standard Miranda warning and obtain an unconditional waiver. After a few brief questions about the failure to appear, you begin to ask questions that relate to the murder. Unless he clearly and unambiguously says that he doesn't want to talk or wants an attorney, you can continue questioning him about the murder until you have a confession.
If the suspect has no outstanding warrants for minor charges, you could simply arrest him for a lesser-included charge for which you have probable cause. In most jurisdictions, PC to arrest for murder would necessarily include PC to arrest for assault or battery; PC to arrest for robbery might include PC to arrest for simple larceny; PC to arrest for forcible rape might also include PC to arrest for assault or unlawful sexual intercourse, and so on. Once you have the confession to the more serious charges, you can add those charges to the arrest and booking reports, to ensure adequate bail.